Mobile machines, such as haul trucks and other types of heavy equipment, are often used to haul material from a load location at which the material is loaded into the machines, to a dump location at which the material is discharged from the machines. In order to maintain productivity and efficiency at a worksite while accomplishing predetermined site goals, travel of the machines at the dump location and positioning of the discharge material should be carefully managed. The need to properly manage the machines at the dump location can become even more important when the machines are working in high-wall operations and are autonomously controlled.
One attempt to control mobile machines at a high-wall operation is described in U.S. Pat. No. 7,966,106 (the '106 patent) issued to Sudou et al. on Jun. 21, 2011. In particular the '106 patent describes a control system for guiding travel of unmanned haul trucks to dump earthen material over a high wall at multiple target locations. The control system begins by receiving a manual survey of an inward edge of a berm that bounds a dump area at a lip of the high wall. A discharge range along the surveyed edge is selected for use, and points are then plotted within the discharge range along the surveyed edge at regular intervals. A normal line (i.e., a line normal to the surveyed edge) is then drawn at each point that extends inward away from the berm a predetermined distance. A parallel line (i.e., a line parallel to the surveyed edge of the berm) is drawn to pass through inward ends of each of the normal lines. The parallel line is then smoothed to create a continuous curve. A starting point is selected on the curve, and another point spaced a predetermined distance from the starting point along the curve is paired with the starting point. A straight line is extended between the paired points, and a trajectory line is extended back toward the berm from a center of the straight line a predetermined distance to end at a dump target. An autonomous mining truck is then guided along each trajectory line until either the dump target is aligned with a center point of a rear axle of the truck or until the berm edge is detected by sensors on the truck. The truck is then stopped and dumping commences.
Although the system of the '106 patent is alleged to help manage dumping at a high-wall edge, the system may be less than optimal. That is, the system of the '106 patent may be complex and inefficient. Specifically, the smoothing operation used to create the continuous curve may be computationally demanding, requiring expensive processing equipment and resulting in delayed control. And the curve, in combination with dump targets always being located a predetermined distance away from the curve, may not account for irregularities in berm contour. By not accounting for these irregularities, it may be possible to dump material before an associated truck has reached the edge of the high wall or for the truck to continuously bump into the berm. Material dumped inside of the berm must then be removed by another machine, resulting in decreased productivity and increased operating costs. Continuously bumping into the berm could also weaken the berm.
The disclosed control system is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art.